SURVIVAL AND ACTIVITY OF LUX-MARKED PHENANTHRENE-DEGRADING PSEUDOMONAS STUTZERI P16 UNDER DIFFERENT CONDITIONS

1Biotechnology and Tissue Engineering Research Center, Faculty of Sciences, Ferdowsi University of Mashhad, Mashhad, I. R. of Iran,

2Department of Molecular and Cell Biology, Institute of Medical Sciences, University of Aberdeen, Aberdeen, UK

Abstract

Viable cell concentration and luminescence activity of P. stutzeri P16 luxAB4 was measured byplate counting and luminometery in sterile and non-sterile soil adjusted to matric potential of -1500, -750 and-30 kPa. Results showed that matric potential had a significant effect on survival and activity of P. stutzeriP16 luxAB4 in soil. P. stutzeri P16 luxAB4 could survive better in Hutner’s minimal medium supplementedwith 1mg l-1 phenanthrene than 1 mg ml-1. However changes in viable cell concentration and luminescenceactivity of lux-marked and wild type strains of P. stutzeri P16 were significantly different in Hutner’smedium, amended with high and low concentrations of phenanthrene. Inoculation of soil with highconcentrations of phenanthrene caused an initial decline in the viable cell concentration of P. stutzeri P16luxAB4 that took a longer time than liquid medium. Changes in viable cell concentration were similar tochanges in luminescence indicating the advantage of Bioluminescence-marker systems for monitoring thesurvival and activity of biodegradative genetically engineered microorganisms (GEMs) in pollutedenvironments. Our results also showed the importance of influence of environmental factors such as matricpotential and pollutant concentration on the fate of GEMs.